fractal-mpi

This program renders Julia sets of the function f(z) = z² + c, coloring interior points by their proximity to the set and exterior points by their divergence rate.

The program reads image and fractal parameters from an input file (see the examples directory), and any of these can be overriden with a command-line argument.

If this is your input file

<fractal>
Cx = -0.8
Cy =  0.156

Lx       = 1.1                # physical size
center_x = 0.55               # center
center_y = 0.05

<image>
Nx       =  480
Ny       =  300

# coloring for interior points
tolerance = 50.0              # what counts as inside?
exp       = 4.0               # exponent
base      = 0.1               # min color

# coloring for exterior points
nstripes = 3
s1 = 10.0
s2 =  5.0
s3 =  3.0
color_1   = DarkChocolate
color_2   = Red # Indigo
color_3   = MidnightBlue

# output file
file      = demj.ppm

<par_end>

You can run the program as

./fractal_mpi.x -i input.frac

or, if you want to override certain options

./fractal_mpi.x -i input.frac fractal/Lx=2 image/tolerance=100